Peachymango.org Data center operators are moving toward IPv6-only operation to simplify addressing, restore end-to-end connectivity, and meet operator and government timelines. Much published IPv6 guidance targets network engineers; this document instead addresses *Site Reliability Engineers (SREs)* and *Software Engineers (SWEs)* who deploy, operate, and debug services in *operator-owned data centers*. It is organized in two parts after IPv6 fundamentals: a *migration program* (transition strategy and observability) and a *technical stack* (hardware, provisioning, transport, applications, and diagnostics). It documents common software and infrastructure gaps and offers practical deployment patterns aligned with the IPv6 Operations (v6ops) working group charter.